A) 20
B) 30
C) 35
D) 40
Correct Answer: B
Solution :
Required time \[=\frac{1}{\frac{1}{1}+\frac{1}{2}+\frac{1}{3}+\frac{1}{6}}=\frac{6}{6+3+2+1}\] \[=\frac{6}{12}h\] or \[\frac{6}{12}\times 60=30\min \]You need to login to perform this action.
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